Is It Bad To Put All New Fish At Once?
- Thread starter joyboy
- Start date
BigbruiserAl
I ain't gettin on no plane fool
So approx 185L take in to account measurements,sand, decor etc your looking about 150L of water which is a good amount. Ill prob still go with daily water changes for the 1st week until the test kit comes 
N0body Of The Goat
Oddball and African riverine fish keeper
How about removing ~25% of the mature media from your existing filter that has been running for 3 years, put it in a new filter and fishless cycle the new filter in a bucket between now and the new fish arrivals?
BigbruiserAl
I ain't gettin on no plane fool
N0body Of The Goat
Oddball and African riverine fish keeper
Because 17, albeit smaller fish, are being added to a system that should have stabilised to support 3 larger fish for three years.
Why risk ammonia and nitrite spikes, when you know you have a relatively large amount of fish arriving, when you can give the bacteria colonies a boost before the new fish arrive? You could do this without buying the new filter, simply placing some of the mature media in the bucket and using a powerhead to aerate the water.
Edit: Having just read TwoTankAmin's response below, I've only now become aware of the vital information that the original 3 fish are being removed from the tank, might have been helpful to have this info in the original post rather than "lurking" within the discussion.
In which case, I agree with TwoTankAmin that the old for new swap should be a lot safer, just keep an eye on the tank stats during the first couple of weeks more often than usual.
TwoTankAmin
Fish Connoisseur
What is known is that there is an established tank with 3 fish in it. One fish was identified as a black moor and so we can easily see what size this fish can be.The two rainbows are a vague description- if they are a couple of pseudomugils they would produce a minimal bio-load but if they are something like boesemani (or bigger) the bio-load is much greater. So nobody responding to this thread, myself included, really knows for certain exactly how much bio-load the OP's tank can handle right now. However, I would bet the bows are not the tiny ones.
Since the OP said the plan is old fish out and new fish in over a relatively short time period, the only issue is do the old fish and the new fish generate similar bioloads. Tetras, even a dozen are light weight and the dwarf gouramis are not real big either. Not are huklis real big. The incoming bio-load is not huge for sure, even if all the fish are adult size.
My best estimate based on the minimal information presented is the trade off is closer to even than not. And if it isn't, I would bet the old fish produce more waste than the new fish. Goldfish are notoriously messy fish and none of the new ones are.
So, I would also bet that as long as the OP does nothing to trash the current bacteria in the system, they will be sufficient to handle all the replacement fish right away. Any shortfall should be minimal and at a low enough level and duration as not to be a serious concern.
To be on the safe side an ammonia test is a good idea as it would confirm what is up. I think this is the only kit needed as it will answer the question fast as to whether there is detectable ammonia or not once the new fish are in. It will also be useful down the road in case of other problems as it allows one to eliminate ammonia as a cause.
Joyboy- BBA hit it pretty much on the head. However, I would go even further and suggest that taking out the old fish, doing one decent water change and soon after putting in the new fish will be perfectly safe. I would say your original assumption that you have all the bacteria you need already is right on the money. If you are worried, then the water changes can't hurt, but then I would also suggest you feed very sparingly until the kits arrives. However, if you can get just the ammonia test kit quickly, you may be able to save yourself a lot of unneeded water changes and a few dollars on other kits as well
Since the OP said the plan is old fish out and new fish in over a relatively short time period, the only issue is do the old fish and the new fish generate similar bioloads. Tetras, even a dozen are light weight and the dwarf gouramis are not real big either. Not are huklis real big. The incoming bio-load is not huge for sure, even if all the fish are adult size.
My best estimate based on the minimal information presented is the trade off is closer to even than not. And if it isn't, I would bet the old fish produce more waste than the new fish. Goldfish are notoriously messy fish and none of the new ones are.
So, I would also bet that as long as the OP does nothing to trash the current bacteria in the system, they will be sufficient to handle all the replacement fish right away. Any shortfall should be minimal and at a low enough level and duration as not to be a serious concern.
To be on the safe side an ammonia test is a good idea as it would confirm what is up. I think this is the only kit needed as it will answer the question fast as to whether there is detectable ammonia or not once the new fish are in. It will also be useful down the road in case of other problems as it allows one to eliminate ammonia as a cause.
Joyboy- BBA hit it pretty much on the head. However, I would go even further and suggest that taking out the old fish, doing one decent water change and soon after putting in the new fish will be perfectly safe. I would say your original assumption that you have all the bacteria you need already is right on the money. If you are worried, then the water changes can't hurt, but then I would also suggest you feed very sparingly until the kits arrives. However, if you can get just the ammonia test kit quickly, you may be able to save yourself a lot of unneeded water changes and a few dollars on other kits as well
If you gave done a full fishless cycle, you can add all of your fish at once. That does not make it a good idea but it is theoretically possible.
joyboy
Fish Fanatic
Ok guys thanks for your help, I canged 40% of my water today and will keep it going for a week! Do i still add the water conditioner and the Safe Chlorine, Chloramine and Ammonia remover everyday when i change the water??
I learned to cycle using this site many many moons ago so to me it's kinda strange to see some say "no" you have to wait for this and that. Old/new water etc etc.
On my fish day I added about 26 fish without issue. Granted 9 of them were neon tetras (which I was told I had to wait a few months before I could add
) The only measure you should consult before adding lots/new fish in one day is the strength of your filter bacs. If you have cycled to the point where 5ppm ammonia and the resulting nitrite are consumed within 12 hours or less then you're good to go.
And on that note, I have long felt that people simply can't wait. They get tired of cycling/looking at an empty tank so they cut corners. Cycling to 3/4 instead of 5ppm and then adding more fish than their bac colony can handle and inevitably fish die. I believe that is the main source behind people advocating you wait before adding certain species like neon tetras. People "did it wrong" and then waiting for this that and such and such before you add them became commonly accepted advice. Also, people who say you should cycle and then add your fish over time don't understand what they are talking about.
My 9 neons were the first fish in on fish day and were given to my nephew 2 years later.
On my fish day I added about 26 fish without issue. Granted 9 of them were neon tetras (which I was told I had to wait a few months before I could add
) The only measure you should consult before adding lots/new fish in one day is the strength of your filter bacs. If you have cycled to the point where 5ppm ammonia and the resulting nitrite are consumed within 12 hours or less then you're good to go.And on that note, I have long felt that people simply can't wait. They get tired of cycling/looking at an empty tank so they cut corners. Cycling to 3/4 instead of 5ppm and then adding more fish than their bac colony can handle and inevitably fish die. I believe that is the main source behind people advocating you wait before adding certain species like neon tetras. People "did it wrong" and then waiting for this that and such and such before you add them became commonly accepted advice. Also, people who say you should cycle and then add your fish over time don't understand what they are talking about.
My 9 neons were the first fish in on fish day and were given to my nephew 2 years later.
joyboy
Fish Fanatic
thanks so much for the detailed answer. I'll get the kit today
TwoTankAmin
Fish Connoisseur
joyboy, you are welcome, glad to help.
Primous you are 100% right about fully stocking a fishlessly cycled tank. One is not requiredYou are don't have to do it that way but you certainly can. That was one of the big attractions of fishless cycling when it first came into use and was put on the internet for fishkeepers to learn. Incidentally, the original internet poster now states dose to a much lower level.
However, I do not agree on the 5 ppm levels for ammonia dosing nor daily dosing either. They are more than is needed and, more often then not, are the direct cause of delays, stalls, too high a level of nitrites and thus pH drops etc.
The water change before stocking is to reduce nitrates etc. clean up the water ;-)
Primous you are 100% right about fully stocking a fishlessly cycled tank. One is not requiredYou are don't have to do it that way but you certainly can. That was one of the big attractions of fishless cycling when it first came into use and was put on the internet for fishkeepers to learn. Incidentally, the original internet poster now states dose to a much lower level.
However, I do not agree on the 5 ppm levels for ammonia dosing nor daily dosing either. They are more than is needed and, more often then not, are the direct cause of delays, stalls, too high a level of nitrites and thus pH drops etc.
The water change before stocking is to reduce nitrates etc. clean up the water ;-)
Don't panic -- the long part of a cycle is getting your bacteria established at all. With a cycled filter they'll grow more quickly, but as suggested, for sure do either daily or every other day water changes of around 30-40%.
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